Readily adjustable extrusion device



Filed March 26, 1947 July 10, 1951 I Q FQRMAZ 2,560,622

READILY ADJUSTABLE EXTRUSION DEVICE 2 Sheets-Sheet 1 a4/ $U W 440/ 5.3 IN vzn'roa CONQAD G. FORMAZ ATTORNEYS July 10, 1951 c. G. FORMAZ 2,550,022.

READILY ADJUSTABLE EXTRUSION DEVICE Filed March 26, 1947 2 Sheets-Sheet 2 CONIZAD G. FORMAZ ATTORNEYS Patented July 10, 1951 UNITED STATES PATENT OFFICE READILY ADJUSTABLE EXTRUSION DEVICE Conrad G. Formaz, Akron, Ohio, assignor to The Firestone Tire & Rubber Company, Akron, Ohio, a corporation of Ohio Application March 26, 1947, Serial No. 737,365

4 Claims. 1

This invention relates to tubing or extruding machines, especially to extrusion machines that can be rapidly changed from the extrusion of one shape to the extrusion of a widely variant shape.

The formation of tread stock for pneumatic tires is one prime example of use for the machine of the invention but it will be realized that the machine can be used for the production of other continuous lengths of plastic material to be formed to desired cross-sectional contours.

In the production of tire treads, the rubber, in plastic condition, is forced through an extrusion die, secured in an extrusion head, by high pressure, and the plastic rubber is formed into a continuous length of a relatively wide, shallow contour, usually varying in thickness laterally of the tread and of minimum depth or thickness at its edge sections. Heretofore, different extrusion heads have been used for each contour or size of tread desired, although in some instances, minor deviations in the tread contour have been produced by changing a die plate associated with the discharge end of the extrusion head. For any appreciable change in size or contour of the extruded material, a new extrusion head would have to be used in place of the head previously used on the machine. As some extruded products may be several inches in thickness and be as much as 24 to 30 inches in width, it will be seen that very high extrusion pressures are used with such extrusion heads, which therefore must be of massive construction, and are usually made from a cast metal block carefully machined and polished to the desired size, with the feed chamber formed in such heads being extremely smooth and a precise, predetermined contour in order to obtain the desired extrusion action. Thus the extrusion heads are quite costly, are somewhat expensive to maintain, and are difficult to change due to their weight and size. It requires several men several hours to change the extrusion head on a large extrusion machine, which, of course, appreciably reduces the production of the machine, especially if the extrusion contour is to be changed very frequently.

The general object of this invention is to avoid and overcome the foregoing and other disadvantages of and objections to known types of extrusion heads, and to provide an extrusion head adapted to be easily modified to generate any of a variety of extrusion shapes and contours.

Another object of the invention is to simplify the change of the contour of the extruded prodnot of an extrusion machine and to reduce the number of changes of an extrusion head required to produce a given variety of extruded shapes.

Another object of the invention is to reduce the cost of an extrusion head change both as to the amount of labor and also as to the inoperative time involved on an extrusion head change.

Yet another object of the invention is to reduce the number of extrusion heads required to produce a desired number of extruded shapes.

A further and more specific object or the invention is to provide at least one removable baffle in an extrusion head to permit substitution of battles to produce a variety of extrusion contours.

The foregoing and other objects and advantages of the invention, which will be made apparent as the specification proceeds, are achieved by the provision of the apparatus shown in the accompanying drawings, wherein:

Fig. 1 is a plan view of an extrusion head embodying the principles of the invention;

Fig. 2 is a front elevation of the extrusion head of Fig. 1;

Figs. 3 and 4 are enlarged vertical sections through the extreme sizes of dies that can be used with the disclosed extrusion head of the invention;

Fig. 5 is a fragmentary longitudinal vertical section, partly in elevation, taken on line 55 of Fig. 2;

Fig. 6 is a rear elevation of the extrusion head of the invention with the section 4! removed; and

Figs. '7 through 14 are fragmentary vertical.

of substantially rectangular shape at its forward or discharge end, as shown in Fig. 7, graduallymerging into a portion of circular cross section, as shown in Fig. 14 at the rearward, or stock receiving end thereof. The circular stock receiving end of the head M) is adapted to be engaged with the mouth of the extrusion chamber of the machine It! to complete the shaping of the extruded material by passage through the extrusion head 4!].

In order to position the extrusion head 40 for easy movement to and from engagement with the' end section ti, such section is provided with a pair of spaced, laterally directed, vertically aligned arms 20 which form a hinge with an apertured offset lug 21 on the extrusion head. A hinge pintle 24 extends through the arms 20 and lug 2| to secure the extrusion head 40 and the end section 41 pivotally together. Pivotal movement of the extrusion head exposes the stock receivin end thereof and is dependent upon the bolts 42 being removed.

Fig. best shows that a die plate 25 may be removably positioned in the mouth or discharge end 43a of chamber 43. Stud bolts 26, with lock nuts 21, engage the head 49 and bear on the top of the die plate 25 to aid in retaining it in place. screws I26 aid in securing the die plate 25-to the head 4|]. A front reenforce bar 28 is also provided to aid in securing the die plate 25 in position being pivotally carried by the extrusion head 40. A lug 29 is formed on the bar 28 at one end thereof and a hinge pintle 3%] extends through lugs 29 and lugs 31 and 32 formed on one edge of the extrusion head 48 to position the bar 28 pivotally on the head.

Fig. 5 shows that the bar 28 may have adjustable support means associated with it to remove some of its weight from the pintle 39. These means may comprise an arm 33 secured to the lower surface of the discharge end of the extrusion head 40 at each side thereof. A screw 34 pivotally secures each arm 23 to the head 40, and a screw 35 with a lock nut E32 thereon is engaged with the free end of each arm 33 and bears on a flat surfaced lug es formed on the lower surface of the bar 28 at each end thereof. The lugs 36 have ramps 31 leading up to their flat surfaces so that pivotal movement of the bar 28 towards the extrusion head moves it to desiredivertical reltionship therewith. Adjustment of the screws 35 controls the vertical position of the bar 28. The bar 28 is retained against the extrusion head 40 and die plate 25 by bolts In order to receive removable means for shaping the material being extruded, the chamber 43 is provided with a pair of diametrically opposed, axially directed recesses 44 formed therein, with undercut ribs 45 formed in the recesses 14 extending substantially the length of the chamber 43. Each of the ribbed recesses is adapted to engage with and position a baliie 46 by means of a dovetail joint with an undercut recess 41, formed in the radially outer surfaces of each of the bafiies 46.

The various cross-sectional views shown in the drawings bring out how the walls of the chamber 43 of the extrusion head All and the shape of the bafiles 4B are of widely varying form throughout the length of the extrusion head. When the extrusion head 46 is pivoted out of engagement with the extrusion machine M, the baliies d6 can be slid or pulled out of engagement with the recesses 44 to permit the insertion of diiferently contoured bafiles for change in the shape of the extruded material. In some instances, the baflles used with the extrusion head 8 may not be of such shape as to force stock flowing through the extrusion head out to the lateral extremities of the mouth 430: so that the die plate used must be adapted to form a contour of less width than the material is forced to assume when passing through the mouth 43a.

Figs. 3 and 4 show die plates 58 and 51 having die openings 54 and 55, respectively, therein representing the extreme sizes of tread formations formable from one extrusion head by variation of the baflie contour. A plurality of stock escape holes '53 may be provided in the die plate 5i adjacent each end thereof for use when the ex- 4 trusion contour is appreciably narrowed. The material flowing through the holes 53 usually is returned to the extrusion machine for reextrusion.

Changes in the extruded shapes may be effected by changing th die plates used in conjunction with the baiile members 46, whereas major changes in the extruded shapes will normally require changing the baffies d5 in the easy manner pointed out hereinbefore. The bafiles 45 may have means, as tapped holes (not shown) provided on their stock receiving ends at the portions thereof abutted against section 3! so that a pull out member could be engaged with the baliles to facilitate sliding or drawing them out of engagement with the recesses 42.

Conduits 5 i it connect to a conduit 52 which may be formed in the head 8 for circulation, usually, ofv cooling fluid therethrough.

Treads or other articles varying through extreme ranges in size, cannot be made on a single extrusion head when such sizes vary several inches in thickness and a foot or more in width. However, the number of extrusion heads required to produce a great variety of extruded shapes, is substantially reduced by the present invention, since practice requires a difierent extrusion head for substantially every extruded shape desired.

In some instances, it may be possible to obtain the desired flow or distribution of plastic material by use of only one bafiie Surface on either the top or bottom of the mouth or throat of an extrusion member.

One embodiment of the invention has been illustrated and described herein in detail but it will be realized that the invention is not restricted to the embodiment disclosed since the scope of the invention is defined in the appended claims.

What is claimed is:

1. An extrusion head for an extrusion machine, said head comprising a substantially tubular member having a chamber extending therethrough of circular cross section at one end for connecting to the remainder of an extrusion machine, said chamber being appreciably longer and narrower at the opposite end for shaping the material flowing therethrough, said chamber having a pair of diametrically opposed longitudinally directed recesses extending substantially the length thereof, and a pair of balile members removably positioned in and engaged with the recesses in said tubular member but extending into said chamber whereby any of a plurality of differently contoured bafile members can be positioned in said tubular member to vary the flow of material through said chamber.

2. In an extrusion head for an extrusion machine, a substantially tubular member having a material transmitting chamber extending therethrough, said chamber bein cylindrical at its receiving end but defining an elongated aperture at its discharge end, said chamber having at least one longitudinally directed recess formed in and extending substantially the length thereof, and a bafiie member removably positioned in and engaged with the walls of said recess in said tubular member whereby any of a plurality of baffles are detachably receivable in said chamber to vary the flow of material there-- through.

3. An extrusion head for an extrusion machine, said head comprising a substantially tubular member having a chamber extending therethrough shaped at one end for receiving: extruded material when connected to an extrusion chamber said chamber being of appreciably difi'erent cross-sectional shape at its discharge end than at its receiving end, a recess formed in the walls of said chamber, said recess extending from the receiving end at least part of the length thereof, and a baflie member removably positioned in and engaged with said recess, said baffle member extending into said chamber and forming a part only of the surface thereof to vary the flow of material flowing through the chamber.

4. An extrusion head for an extrusion machine, said head having a work transmitting passage therethrough, a groove formed in the wall of said openin and extending from its work receiving end substantially the length thereof, a bafile member removably positioned in and engaged with the walls of said groove, said baffie extending into said opening and having a contour which complements the contour of said 6 opening whereby the contour of the openin may be changed by replacing one bafile with another of difierent contour.

CONRAD G. FORMAZ.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

1. AN EXTRUSION HEAD FOR AN EXTRUSION MACHINE, SAID HEAD COMPRISING A SUBSTANTIALLY TUBULAR MEMBER HAVING A CHAMBER EXTENDING THERETHROUGH OF CIRCULAR CROSS SECTION AT ONE END FOR CONNECTING TO THE REMAINDER OF AN EXTRUSION MACHINE, SAID CHAMBER BEING APPRECIABLY LONGER AND NARROWER AT THE OPPOSITE END FOR SHAPING THE MATERIAL FLOWING THERETHROUGH, SAID CHAMBER HAVING A PAIR OF DIAMETRICALLY OPPOSED LONGITUDINALLY DIRECTED RECESSES EXTENDING SUBSTANTIALLY THE LENGTH THEREOF, AND A PAIR OF BAFFLE MEMBERS REMOVABLY POSITIONED IN AND ENGAGED WITH THE RECESSES IN SAID TUBULAR MEMBER BUT EXTENDING INTO SAID CHAMBER WHEREBY ANY OF A PLURALITY OF DIFFERENTLY CONTOURED BAFFLE MEMBERS CAN BE POSITIONED IN SAID TUBULAR MEMBER TO VARY THE FLOW OF MATERIAL THROUGH SAID CHAMBER. 